linux-kernel - [PATCH 2/4] tpm_tis: Move CRC check to generic send routine

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Date:   Mon, 5 Jun 2023 19:52:48 +0200
From:   Alexander Steffen <Alexander.Steffen@...ineon.com>
To:     <jarkko@...nel.org>, <linux-integrity@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>
CC:     Alexander Steffen <Alexander.Steffen@...ineon.com>
Subject: [PATCH 2/4] tpm_tis: Move CRC check to generic send routine

The CRC functionality is initialized before tpm_tis_core, so it can be used
on all code paths within the module. Therefore, move the CRC check to the
generic send routine, that also contains all other checks for successful
command transmission, so that all those checks are in one place.

Also, this ensures that tpm_tis_ready is called when a CRC failure is
detected, to clear the invalid data from the TPM, which did not happen
previously.

Change-Id: I334abe9accc45efa679e23d391705322886bd0e3
Signed-off-by: Alexander Steffen <Alexander.Steffen@...ineon.com>
---
 drivers/char/tpm/tpm_tis_core.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/drivers/char/tpm/tpm_tis_core.c b/drivers/char/tpm/tpm_tis_core.c
index aaaa136044ae..5ddaf24518be 100644
--- a/drivers/char/tpm/tpm_tis_core.c
+++ b/drivers/char/tpm/tpm_tis_core.c
@@ -466,6 +466,12 @@ static int tpm_tis_send_data(struct tpm_chip *chip, const u8 *buf, size_t len)
 		goto out_err;
 	}
 
+	rc = tpm_tis_verify_crc(priv, len, buf);
+	if (rc < 0) {
+		dev_err(&chip->dev, "CRC mismatch for command.\n");
+		goto out_err;
+	}
+
 	return 0;
 
 out_err:
@@ -510,12 +516,6 @@ static int tpm_tis_send_main(struct tpm_chip *chip, const u8 *buf, size_t len)
 	if (rc < 0)
 		return rc;
 
-	rc = tpm_tis_verify_crc(priv, len, buf);
-	if (rc < 0) {
-		dev_err(&chip->dev, "CRC mismatch for command.\n");
-		return rc;
-	}
-
 	/* go and do it */
 	rc = tpm_tis_write8(priv, TPM_STS(priv->locality), TPM_STS_GO);
 	if (rc < 0)
-- 
2.34.1